Tinycircuits small form factor tinycircuits asd2412 r lg the tinycircuits tinyshield circle edge led board allows some cool and easy led effects using only six io signals this board includes 21 leds mounted around the outside of the board to form a full circle and is designed to be placed on the top of the tinyshield stack the leds are driven using charlieplexing which is a technique for controlling of multiple leds using fewer io signals available with red 73 4672 green 73 4764 and